SMPS Rectifier circuit burned up a resistor

[budm]

Re: SMPS Rectifier circuit burned up a resistor

The really bad part of this amp (direct coupled output stages) is that it does not have any speaker protection (speaker relays) that will disconnect the speaker from the output when it detects DC at the output so when the output MOSFET shorted out, it will not dump 24VDC in to the speakers.
Another funny thing on the spec of this amp is rated at 1000W but the power consumption is only 90W.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

Here's a pic of the damage for everybody's entertainment. I have more, I'll post them in a bit

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Re: SMPS Rectifier circuit burned up a resistor

believe it or not, after cleaning it up, it looks like the only damage was to the legs of the IC. but who knows right now. I'm just sort of staring at it in amazement of how bad it went up

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

The really bad part of this amp (direct coupled output stages) is that it does not have any speaker protection (speaker relays) that will disconnect the speaker from the output when it detects DC at the output so when the output MOSFET shorted out, it will not dump 24VDC in to the speakers.
Another funny thing on the spec of this amp is rated at 1000W but the power consumption is only 90W.

yeah I need to hook the sub up to another source and see if it's still good.

I'd noticed the 90w input vs 1000w output. I think they're playing games with ohm ratings and specing...

like how cheap car stereo amps will claim to be 250w, but thats at 2 ohms, when they're really 125w amps, unless you happen to want to hook a Jensen or something ridiculous to a DVC high quality sub in parallel...

[budm]

Re: SMPS Rectifier circuit burned up a resistor

Yeah, how do you get more power than what you put in, if they can do that, they will be rich and build a lot of power plants.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

It did seem to be pushing around 100 watts through the 4ohm sub though, but then thats at 4ohms...

It's also plausible that the 90w power consumption rating is at a very low volume so that they could get a high energy star rating. Sort of like how the 602hp 2013 GT500 gets 24mpg....

Figures lie and liars figure....

[budm]

Re: SMPS Rectifier circuit burned up a resistor

The power supply is not rated at 1000W, so no matter what you do you cannot get more than what you put in, 1000W switching supply will not fit in that chassis. Power is = I x E, you can get the same power if yiou increase the voltage into higher resistance load or lower voltage with lower resistance load. For 1000W output with 90% effeiency, you will will need more than 1000W input power. You can look at lable on the back of the unit, it will have max Volltage and the current rating printed on it.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

yeah, I know about thermodynamics. just like gold vs bronze cert on a PC PSU.

it does say 90w on the back. also noticed it refers to itself as a "class b digital apparatus"

not sure if they are trying to say it's supposedly a class b amp? or is it just subpar on all levels, lol

[budm]

Re: SMPS Rectifier circuit burned up a resistor

That is FCC Class B rating due to switching power supply and the swtiching Class D amplifiers that radiate lots of High frequency.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

Oh cool, I never payed much attention to FCC ratings.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

ok, well the sub is still good and I'm going to source an external amp for it.

I have two questions now though, since I can't find a good transformer for the sub, and I plan to give up on the center channel...

do you think the RCA sub output is already frequency controlled by the input/processor board? or will I need an external crossover?

and also, should I lift the burnt IC off the amplifier board before reassembly so it doesnt fry the switching power supply? or should I leave it alone and assume that it's bunt out and no longer poses a threat?

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Re: SMPS Rectifier circuit burned up a resistor

ok, I decided to just take a look at how it seemed the etch was going on the PCB's and decided to remove the burnt IC, it works fine and no longer makes a blown electicals smell any more.

decided to test the RCA sub output and ran a car stereo RCA wire from it to the setup in my bedroom (2 12" car stereo subs built into a waterbed frame in a cross firing sealed bandpass fashion, with a 450w car stereo 2 channel amp and an active crossover hooked to a 10amp power supply) and the RCA output is indeed actively controlled by the same sub filtering circuit as the amplified sub output. so now I'm on the hunt for a cheap home amp for the sub in the living room.

any suggestions? granted, the living room will be only "quadraphonic" (4.1) but I can daisy chain the audio through the HDTV and use the tv's stereo HD speakers as my center channel for theatrical use, and for music the HTIB receiver has a dolby "music" setting that is in essence 4.1 output. so I suppose this will do, since it's just a setup for the living room, in which we spend little listening time.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

hrrrmmm, stumbled upon this and it made me wonder...

http://www.parts-express.com/pe/show...number=320-307

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Re: SMPS Rectifier circuit burned up a resistor

also wonder if this lil guy could be built into the case to provide me with 2 4ohm 100w subwoofer outputs....

http://www.parts-express.com/pe/show...number=320-334

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Re: SMPS Rectifier circuit burned up a resistor

then I found this, which would mount to the outside of the the sub enclosure: http://blujay.com/item/DAYTON-MODEL-...050102-3091530

or this, which I would have to build a case for, as I dont want to cut holes in the nice stillwater enclosure: http://www.apexjr.com/CVT200S.htm

any opinions as to which way would probably be best? I'm leaning towards the dayton, as it would be the most straight forward to use...

[budm]

Re: SMPS Rectifier circuit burned up a resistor

I would go with sub woofer plate amp, non Class D type.
http://www.parts-express.com/cat/sub...amplifiers/332

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Re: SMPS Rectifier circuit burned up a resistor

is this dayton different than the one I posted before?

http://www.parts-express.com/pe/show...number=300-802

I'm not trying to spend more than $100 on an amp for a sub in a room with an RCA HTIB for the receiver. this setup is anything BUT an audiophile setup. not to mention the power consumption of a class a amp.

I've got a GAS son of ampazilla and a Carver sonic holographer if I wanted to get some nice modern studio monitors (like m-audio maybe) and hook that directly to a high end audio production soundcard (also probably m-audio)

but this is a low end stereo for playing music from thumb drives and hooking up to an old hitachi digital rear projection HDTV... nothing in that room is top notch. I dont really care about the living room. I just like to get things I already have to work...

[budm]

Re: SMPS Rectifier circuit burned up a resistor

http://www.parts-express.com/cat/sub...amplifiers/332
Any one of those that is not Class D will be fine. you had Link to DAYTON from other website, Part express also sells Dayton amps.
this one?
http://blujay.com/item/DAYTON-MODEL-...050102-3091530

"GAS son of ampazilla and a Carver sonic holographer" Good stuff from the 70's used to repair them. SAE, Carver the 7" CUBE, Phase Linear 400, 700, Original Fisher, Scott, Mc Intosh, good old stuff.

[Home_Command_Center]

Re: SMPS Rectifier circuit burned up a resistor

ah, didnt catch the source difference.

my main point is when selecting an amp for a sub that is going to be hooked to a class d HTIB we don't really need to concern ourselves with a class a amp for the sub. in fact, class a for mids and highs with a class d sub amp is fairly common practice.

is there any practical reason to pay more for a class a amp for the sub only when the satellite speakers are going to be driven by a low tech class d amplifier circuit?

[siski123]

Re: SMPS Rectifier circuit burned up a resistor

please can someone give me the resistance R202 worth it since i how the same problem with rca RT2870 - rt2770 smps bd mp